Mr.Bape

ok so I have a 2007 V6 mustang, and I'm having difficulties with the interior dash lighting. for some reason when I have my headlights on, the gauges, radio lighting etc. work as they should. but when I turn on my headlights at night, the gauges etc. light up very dimmed. I was gonna take it to a ford retailer for service but the next available appointment is the 22! any suggestions? the only things I have plugged in are my ipod and phone charger, and those were not the source of the problem.